More elegantly handle internet disconnection (offline mode?)

[deanputney]

Right now when the Internet disconnects, downforacross displays a "disconnected, please refresh" message. This message completely overrides gameplay– the game cannot continue until the internet connection is restored and the page is completely refreshed.

It'd be great if a puzzle could continue to be worked on while the Internet is not accessible. This should still be visibly notified to the user, but non-blocking. Functionality which requires the Internet (e.g. multiplayer support) would need to be disabled while the Internet is inactive and then resolved when it is restored.

This issue was noticed primarily on mobile browsers, Safari and Chrome for iPhone. Here's the browser info for my phone: https://whatismybrowser.com/w/39K85EA

[Anthuang]

Wanted to bump this, I take the subway everyday so having offline mode would be awesome!

Some rough idea for how this could be implemented (note: I have little context on your code base):

• Each cell could additionally store the timestamp at which a change is made.
• When offline, changes to the puzzle can be buffered locally.
• When going back online, these changes can be written to the affected cells, with conflicts resolved by taking the latest changes based on timestamp.

This is obviously not perfect due to clock drift, but perhaps a viable initial implementation.